1. Field of the Invention
The present invention relates to a hand-operated valve for controlling a flow rate of fluid through manual operation of a screw mechanism, and more particularly to a hand-operated valve with a locking mechanism which precludes actuation of a screw mechanism when the valve is in a closed state.
2. Description of Related Art
Heretofore, there has been known a hand-operated valve provided with a locking mechanism in addition of a screw mechanism. Such a valve is disclosed in, for example, Japanese Patent Unexamined Publication 2000-97368. As shown in FIG. 10, this valve includes a main body 103 internally provided with a valve seat and a lock member 101 having an inverse L-shape, fixed to the main body 103. The lock member 101 is provided with a pinch part 101a surrounding the lower periphery of a handle 102 connected with a valve body. A lock bolt 104 is fastened to contract the diameter of the pinch part 101a, thereby locking the handle 102 to the main body 103.
The above conventional hand-operated valve with the locking mechanism, however, has the following disadvantages. To lock or unlock the handle 102, a worker has to operate the lock bolt 104 while firmly holding the handle 102 by one hand against rotation. This is to prevent even a little rotation of the handle 102 when the lock bolt 104 is operated, for example, unfastened to unlock the handle 102. If the handle 102 is unintentionally rotated even a little at the unfastening of the bolt 104, the valve is allowed to open, resulting in a fluid leak. Thus the worker must operate the lock bolt 104 by one hand with the other hand holding the handle 102. This would reduce a workability.
The above hand-operated valve is often used in a process gas supplying apparatus in a semiconductor manufacturing system. A recent tendency for this process gas supplying apparatus is toward an integration in a small area. However, the conventional hand-operated valve needs insertion of a hexagon nut or the like in a lateral direction to mount the locking mechanism to the valve, which results in wasted space.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide a hand-operated valve with a locking mechanism capable of eliminating a need for a worker to hold a handle in operating the locking mechanism, thereby improving workability, and furthermore capable of allowing mounting in a small area without a need to provide wasted space.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the purpose of the invention, there is provided a hand-operated valve with a locking mechanism including: a valve main body including a valve body, a valve seat, and a screw mechanism which is actuated to bring the valve body into contact/noncontact with the valve seat; a locking mechanism for preventing actuation of the screw mechanism during a time when the valve body is in contact with the valve seat to close the valve; an operating member connected to the valve main body, for actuating the screw mechanism for contact/noncontact operation of the valve body with respect to the valve seat to thereby close/open the valve; and a play providing mechanism interposed in a connection between the operating member and the valve main body, for preventing the actuation of the screw mechanism during a predetermined stage of operation of the operating member.
In another aspect of the invention, a hand-operated valve with a locking mechanism includes: a valve main body including a valve body, a valve seat, and a screw mechanism which is actuated to bring the valve body into contact/noncontact with the valve seat; a padlock for preventing actuation of the screw mechanism during a time when the valve body is in contact with the valve seat to close the valve; an operating member connected to the valve main body, for actuating the screw mechanism for contact/noncontact operation of the valve body with respect to the valve seat to thereby close/open the valve; and a play providing mechanism interposed in a connection between the operating member and the valve main body, for preventing the actuation of the screw mechanism during a predetermined stage of operation of the operating member.